This horizontal mixer has high mixing degree and less residue, which is suitable for mixing organic fertilizer and inorganic fertilizer. The specific characteristics are: the materials are fully mixed, thus improving the mixing uniformity. The use of a novel rotor structure allows the clearance between the rotor and the casing to be adjusted to close to zero, effectively reducing the residual amount of materials. The special rotor design of the machine can also crush large materials. The overall structure is more reasonable, the appearance is beautiful, and the operation and maintenance are convenient.